IE42346B1 - Method and apparatus for comminuting marine algae and the resulting product - Google Patents

Abstract

1513449 Treating seaweed R HERVE and D ROULLIER 14 Oct 1975 [18 Oct 1974] 42101/75 Heading A1X [Also in Division B2] Seaweed, particularly of the pheophyceae and chlorophyceae classes, is comminuted at below -20‹C to produce a wet paste-mix with a mean particle size below 100 micrometres. The seaweed is freshly cut and frozen and fed by a hopper 1 into a comminutor 2 which has knives or blades 6 on a shaft 5 cooperable with a bar or blade carrier 7. Shredded material is fed by a belt 10 to a comminutor 3 which comprises opposed relatively rotatable toothed discs, viz a stator 13 and rotor 14. Ground material is delivered by a belt 35 to a series pair of three-roller mills 30, 31. Coolant viz liquid nitrogen is injected via ports 19, 20 to the comminutors 2, 3, in response to control signals from sensors 26, 27 to valves 24, 25. The liquid nitrogen is stored in a vessel 21. Cooling may alternatively be effected by pipes in or near the walls of the comminutors 2, 3. The comminutors are thermally jacketted. The roller mills have convex cambered rollers 30, 31. The prepared paste is mixed with water for spraying as a growth promoting agricultural fertilizer.

Description

The present invention relates to a method and apparatus for comminuting marine algae and to tha resulting product.

In a broken-down state, green and brown marine algae are capable of many applications,-- in particular in the field.of agriculture, due to the; active substances which they contain, among which are, in particular, vitamins and phytohormones. Known processes for comminuting, i.e. reducing the particle size of algae, are performed at ambient temperature with algae which have previously been dried in the atmosphere or dehydrated with hot air, or both, which has the serious disadvantage that it destroys a large proportion of the active substances contained in the algae.

The present invention has as an object to overcome this disadvantage and to provide a method of and an apparatus for comminuting algae by means of which it is possible to obtain an algae mix which is rich in active substances.

Accordingly, the invention consists in a method of comminuting fresh algae, which consists in carrying out a comminuting operation on said algae while maintaining said algae at a temperature lower than ~20aC.

Preferably the comminuting temperature lies within the range between -30° and -100°C. It is advantageous 2346 - 3 for the fresh algae to be frozen before being comminuted at a temperature of less than -20°.

In accordance with a feature of the method according to the invention, the broken down algae are comminuted by crushing to the form of a wet paste-mix, the particles contained in which mix are of a mean size less than 100 micrometres and preferably less than 50 micrometres.

The invention also consists in a comminutor, i.e. comminuting apparatus, which comprises a comminuting assembly and means to maintain the temperature within said assembly at a level lower than -20°C, and preferably one between -30° and -100°C, by means of a cooling agent.

In accordance with a feature of the apparatus according to the invention, the apparatus also includes at least one roller reducer into which the matter emerging from the first reducing i.e. comminuting assembly is able to be fad.

The fact that the comminuting assembly is cooled, on the one hand prevents the algae from warming up in a disadvantageous way and, on the other hand, enables' the frozen algae to be reduced efficiently, the algae being broken down into fragments. The fact that the fresh algae are frozen beforehand enables a saving to be made of cooling agent during the actual comminuting operation. Advantageously, the broken down algae are crushed to produce a wet paste-mix, the particles in which are sufficiently small in size to enable it to be used in sprayers. '42346 - 4 Other features and advantages of the method and apparatus according to the invention will become apparent from perusal of the following description of a particular embodiment thereof, which is given by way of non-limiting illustration with reference to the accompanying drawing comprising one Figure, which is a schematic view of a comminuting apparatus according to the invention.

Referring now to the drawing, the algae intended for comminution are frozen when freshly, cut up at a temperature less than -20°C e.g. between -20°C and -50°C. The frozen algae are fed by means of a supply hopper 1 into a comminuting assembly which consists of a bladed comminutor 2 and a toothed comminutor 3, which are connected by a passage 4.

The bladed comminutor 2 includes a shaft 5 which carries knives or blades 6 and which is driven round by any desired known means (which are not shown), and a fixed bar 7 which, is adjacent the path followed by the ends of the blades and may possibly itself be provided with a blade. After having been shredded, the algae are discharged from the lower part of the bladed comminutor 2 via a passage 8 and pass onto a feeder 9 . Feeder 9 is formed by a continuous horizon25 tai belt 10 which runs on a drive pulley 11, which is driven by a motor, which is not shown, and a return pulley 12. Feeder 9 supplies the toothed comminutor 3 via a passage 4 in the form of a funnel. The toothed comminutor 3 includes a coaxial stator 13 and rotor 14 the axes of which are horizontal. The stator 13 contains an axial opening and the algae which pass through this opening are broken down between the stator - 5 13 and the rotor 14 by means of the teeth with which the opposing faces of the stator and rotor are provided, the ends of the teeth on the stator projecting between the ends of the teeth on the rotor and vice versa.

The rotor 14 is driven by any convenient known motor (not shown) at a speed of the order of 8,000 revolutions per minute. In leaving the toothed comminutor 3, the ground algae are expelled from the gap between the stator 13 and rotor 14 and are deposited in a second hopper 15 via a passage 16.

The bladed comminutor 2 is located at a higher level than the toothed comminutor 3 and rests on a framework 17 which also supports the feeder 9. The comminutor 3 is arranged above hopper 15 and is suppor15 ted by a framework 18.

In order that the frozen algae may be comminuted efficiently, the comminutor assembly is held at a temperature of less than -20°C. To this end, the working areas of the comminutors 2 and 3 are cooled by a cooling agent. For this purpose, injection ports such as 19 and 20, which may for example be so arranged as to form banks of ports, open onto the working areas of the bladed and toothed comminutors respectively and are connected to a source of cooling agent, such as a container 21 of liquid nitrogen, by means of pipes 22 and 23. The flow of liquid nitrogen through pipes 22 and 23 is controlled by regulator valves 24 and 25 respectively. So that the temperature in the working areas of the bladed and toothed comminutors can be maintained at a desired level, at least one temperature probe such as 26 or 27 respectively, is arranged in each of the said areas and is connected to a member 28 - 6 and 29 respectively, for controlling the regulator valves 24 and 25. Control members 28 and 29 may be adjusted to suit the temperature required in the working areas of the comminutors. This temperature will preferably be between -30°C and -1OO°C, and may for example be close to -50°C, with the object on the one hand of maintaining the temperature of the algae within the assembly formed by comminutors 2 and 3 and passage 4 at a level below -20°C, so that the algae will remain frozen, and on the other hand to avoid too great a consumption of liquid nitrogen.

Cooling by injecting liquid nitrogen has proved to be effective due to the evaporation of the liquid nitrogen as it emerges from the injection ports. It Is however also possible for the cooling to be carried out by circulating liquid nitrogen through pipes arranged in or near the walls of the respective working areas of comminutors 2 and 3, and in this case the flow of liquid nitrogen through the pipes may be controlled by a regulating arrangement which consists of at least one temperature sensor, ohe control member and one regulating valve as described above. In addition, it has proved preferable for the walls of comminutors 2 and 3, for example, to be thermally insulated by cove25 ring them on the outside with insulating materials such as polyurethanes, polyesters, etc.

In the form in which they are received in hopper 15, the fragments of broken-down algae have a mean size of the order of 0.1 to 0.5 millimetres and are thus too large to be used subsequently in sprayers. It is therefore advantageous for the broken-down algae to be fed on to one or more further size reducers, such as - 7 triple roller reducers similar to 30 and 31, in order to reduce this mean size to less than 100 micrometres and preferably to 50 micrometres.

The first roller size reducer 30 has, in a known way, three rollers 32, 33 and 34 whose axes are mutually parallel,with the roughing-down roller 32 and the collecting roller 34 pressing on either side against the centre roller 33 and both turning in the same direction, which is opposite from that of roller 33.

The broken-down algae coming from the comminuting assembly which are deposited in hopper 15 are fed onto a conveyor belt 35 which drops them between the roughing-down roller 32 and the centre roller 33. The algae are successively crushed between rollers 32 and 33 and 33 and 34 and are tipped from roller 34 into the output 36 from roller reducer 30. The matter coming from roller reducer 30 is fed on by an endless conveyor belt 37 to the input of the second tripleroller reducer 31. The latter is similar in structure and operation to reducer 30 and has three rollers 38, and 40 which are roughing-down centre and collecting rollers respectively. The algae crushed between rollers 38, 39 and 40 are collected at the output 41 of reducer 31. Conveyor belts 35 and 37 and reducers 30 and 31 are driven by means which are not shown.

Advantageously, the roughing-down and collecting rollers 30 and 31 are made slightly convex in outline while the centre roller is straight sided. Preferably the camber of the roughing-down roller is between one and eight hundredths of a millimetre, and preferably between two and four hundredths of a millimetre, that is to say that the radius of the roller at the centre - 8 is greater by one to eight hundredths of a millimetre, and preferably by two to four hundredths of a millimetre, than the radius at the ends of the roller. The collecting roller has a camber of between nought and five hundredths of a millimetre and preferably one and three hundredths of a millimetre. When the camber of the rollers is within the limits quoted above, this allows the matter to pass between them satisfactorily. The pieces of algae coming from the first comminutor assembly warm up in hopper 15, where they may be left to wait for some time. The phase of crushing by means of the roller reducers takes place at atribient temperature, the temperature of the broken down and crushed algae changing from approximately -1O°C to +15°C, which enables a wet paste-mix to be obtained at output 41. This paste contains particles the size of.which is less than’ 100 micrometres and on average is between 10 and 50 micrometres. The rollers of each of the roller reducers are preferably driven at the highest possible speed in order to obtain maximum output at outlet 41.

The use of two triple roller reducers,the bodies of the rollers of which are 1 metre long in the case of the first reducer and 1.3 metres long in the case of the second reducer, with a diameter of 0.4 metres, and of which the roughing-down rollers have a camber of three hundredths of a millimetre and the collecting rollers a camber of one hundredth of a millimetre, allows a paste to be obtained,the particles in which have a mean size of twenty micrometres.

The method and apparatus which have just been described are used on green and brown marine algae 2346 - 9 collected at sea, which may for example, be stored, after being cut up, on a boat having a fresh-storage well. The brown and green algae which are taken belong to the classes of pheophyceae and chlorophyceae and are such as the laminariae(laminaria flexicaulis for example) the fuci (fucus spiralis for example) and the ascophyllal (ascophyllum modosum for example) and other related types.

Once landed, the algae are preferably stored in cold chambers to allow them to be frozen, which on the one hand allows them to be kept fresh and on the other prevents the excessive consumption of liquid nitrogen which would be required if fresh algae were fed into the comminutor assembly without having first been frozen.

The raw product obtained by means of the method or apparatus described above takes the form of a thick green paste the pH of which is approximately 4.8, which is stable under normal storage conditions at ambient temperature and which can be mixed with water simply by stirring. The product contains in particular chlorophyll, algin and laminarin, the combined content of which by weight is equal to approximately 15 to 20% of the weight of dry solids and it also contains phytohormones, in particular gibberillins, amino-acids, and elements such as sulphur, magnesium, iodine and other trace elements.

It will be noted that when the fresh algae are comminuted when cold, all the substances which were originally contained in the algae can be found in the end product whereas known methods, in which the algae are dried in the open air and/or are dehydrated with - 10 hot air before comminution and after being washed in soft water, have the drawback that they cause the irreparable loSs of some or all of the vitamins and phytohormones at temperatures above 60°C and that of the laminarin and algin.

Table I below gives, by way of illustration, the amounts of the various constituents found in a raw product according to the invention, the amounts being given in relation to the weight of the raw product.

The amounts may vary with the time of collection and the relative proportions of the types of algae involved.

TABLE I. Total nitrogen from 4.50 to 5.50% Ammoniacal nitrogen n 0.55 0.65% Nitric nitrogen II 0.90 1.00% Dreic nitrogen II 2.45 3.00% Organic nitrogen n 0.55 0.80% Total Sulphur II 0.20 0.40% (expressed as S) Sulphates Cexpressed tl 0.10 0.17% (as S) Iodine ll 170.00 250 mg/kg Iron tt 310 n 460 mgAg Magnesium It 800 1200 mgAg Copper II 20 35 mg/kg Carotene (provitamin A) it 1 1.50 mgAg Vitamin C ir 90 130 ijigAg Vitamin B 12 ir 2.75 4.25 micro- grammes/kg Total phosphoric acid II 3.90 4.80% Potassium II 2,70 3.35% Weight of dry solids II 27 30.00% - 11 The raw material produced by practicing the invention is able to be used in the agricultural field and may be employed as a growth promoting substance for plants, in particular by spraying a composition which contains it in solution or suspension in water onto the plants. Its growth-promoting effect on plants is illustrated by the results of trials which are given, by way of illustration, in Tables II, III, IV- V and VI below. It can be seen from Table I that the produce according to the invention contains insufficient quantities of nitrogen and potassium to allow it to be considered as a leaf fertiliser. It is however possible for the product to be used with advantage in combination with leaf fertilisers and similar products.

Table II gives the results of comparative trials carried out on three plots of land A, B, C which were planted with UGNI BLANC varieties of COGNAC vine, plots A, B and C being respectively a control plot, a plot which was treated by spreading with five 15 kg/ hectare applications of leaf fertiliser, and a plot which was treated by spraying with four 12 kg/hectare applications of the raw product according to the invention with water added.

TABLE II.

A : B : C Hectolitres of wine per hectare: 132.2 : 151.7 : 167.1 Proportional yields of pure : 100 : alcohol per hectare 103 : 119 It was noted that the vines on plot C showed considerably less coulure and shot berries and that their '43344 - 12 fruit developed better, which explains the greater quantitative and alcohol yields from the plants treated with the product made according to the invention.

Table III gives the results of comparative trials 5 carried out on two plots A and B planted with apple trees of the GOLDEN variety, plot A being a control plot and plot B having been treated by spraying with four 12 kg/hectare applications of the product according to the invention with water added.

TABLE III.

Sise of fruit picked in mm. : 60/65 : 65/70 : 70/75 : 75/80: 80 Percentage of A fruit picked 12.50 : 50.00 : 22.50 : 13.05 : 1.20 : 0.75 B 0.96 : 16.90 : 18.10 ; 37.50 : 17^87: 8.67 73/47 These results show that the fruit picked from trees which had been treated with a product accord!ng to the invention were larger and more uniform in size.

Table IV gives the results of comparative trials 15 carried out on two plots A and B planted with strawberry plants.of the TIOGA variety and two plots C and D which were planted with strawberry plants of the ALISO variety, plots A and C being control plots and plots B and D being sprayed with three 12 kg/hectare applications of raw product according to the invention with water added. 23 16 - 13 TABLE IV.

Time of picking Amount picked in kg/hectare A B C D 15 to 31 March 1,124 1,712 888 2,313 1 to 15 April 2,461 2,676 2,688 3,250 16 to 30 April 1,765 1,765 1,625 1,875 Total . 5Z 350 6,153 5,201 7,438 These results demonstrate the better yields and the earlier fruiting of the strawberry plants treated with the product in accordance with the invention.

Table V gives the results of comparative trials carried out on plots A, B and C which were planted with potatoes of the SIRTENA variety, with plot A being a control plot, plot B being sprayed with 3 kg/hectare of product according to the invention before the potatoes were earthed up, and plot C being sprayed with 7 kg/hectare of product, consisting of 3.5 kg/hectare before earthing up and 3.5 kg/hectare before flowering.

TABLE V.

ABC Proportional yield per hectare 100 129 137 Percentage of potatoes gathered larger than 28 mm in size 85.5% 90% 92.7% These results show an increase in yield and size for potatoes on the plots treated with a product according to the invention.

Finally, Table VI shows the results of comparative tests carried out on greenhouse-grown lettuces, lettuces A being the controls, lettuces B being treated with a leaf fertilizer under the normal conditions, and -14 lettuces C being treated with a product according to the invention with added water, the quantity of raw product used being equivalent to 12 kg/hectare.

TABLE VI.

A B C Dry weight of 3 lettuces (grams) 16.5 16 18.5 Chlorophyll A (in mg per 100 g of fresh matter) 0.401 0.401 0.487 Chlorophyll B (in mg per 100 g of fresh matter) 0.240 0.245 0.282 Carotene (provitamin A) (in mg per 100 g of fresh matter) 0.278 0.272 0.419 These results show the effect of the product according tg the invention on the chlorophyll and carotene contents. The result of the increase in these contents is that the lettuces develop earlier and to a greater extent, which is confirmed by the measurements of dry weight.

It is clear from the trials which were carried out that the product according to the invention has a substantial effect when used, possibly over a number of applications, in a total amount approximately equal to at least 3.5 kg/hectare and preferably equal to an average of between 7.5 and 15 kg of raw product (i.e. between 2.2 and 4.5 kg of dry product) per hectare.

The addition of water is necessary so that the product can be sprayed over a large area.

Claims (11)

1. CLAIMS;

1. A method of comminuting fresh algae, which consists in carrying out a comminuting operation on said algae while maintaining said algae at a temperature lower than -20°C.

2. A method according to Claim 1, wherein said temperature lies within the range -30°C to -100°C.

3. A method according to Claim 1 or 2, wherein the fresh algae are frozen at a temperature of leas than -20°C before being comminuted.

4. A method according to Claim 1, 2 or 3, wherein said algae, after being broken down, are comminuted by crushing into the form of a wet paste-mix, the mean size of the particles in which is less than 100 micrometres.

5. Apparatus suitable for comminuting frozen algae, including a bladed comminutor, means capable of feeding said bladed comminutor with frozen algae, a toothed comminutor, first transfer means for transferring cut frozen algae from an output of said bladed comminutor to said toothed comminutor, cooling means capable of maintaining the temperature in the working zones of said comminutors below -20°C by means of a cooling agent, at least one roller reducer operating at ambient temperature and comprising at least two rotatable rollers pressed one against the other and capable of rotating in opposite directions, and second transfer means for transferring comminuted frozen algae from an output of said toothed comminutor to said roller reducer whereby said algae is reduced into a paste by crushing between said rollers.

6. Apparatus as claimed in Claim 5, wherein the roller reducers each contain three rollers having mutually parallel axes, said rollers comprising a roughing-down . roller, a centre roller and a collecting roller respectively, -. 42340 16 the roughin.g-d.own and collecting rollers pressing on either side against the centre roller, and the roughing-down and collecting rollers each having a convex outline with a camber of between 1 and 8/100ths of a millimetre in the case of 5 the roughing-down roller and a camber between 0 and 5/lOOths of a millimetre in the case of the collecting roller, the centre roller being straight-sided, as seen in section.

7. An algae product whenever produced by comminuting green and/or brown marine algae belonging to the chloro10 phyceae and/or pheophyceae types, while maintaining said marine algae at a temperature of less than -20°C to obtain pieces of 0.1 to 0.5 mm in size, and reducing the comminuted algae by crushing to obtain, at ambient temperature, a paste the particles in which have a mean size of less than 15 100 microns.

8. A product according to Claim 7, which contains at least 15% by weight in relation to the weight of the dry product of the group formed by chlorophyll, lamlnarin and algin, at least 3 mg of provitamin A or carotene per kg of 20 dry product, and at least 270 mg of vitamin C per kg of dry product.

9. A growth-promoting composition to promote the growth of plants, which contain a product according to Claim 7 in solution or suspension in water. 25

10. A method of comminuting fresh algae substantially as hereinbefore described with reference to the accompanying drawing.

11. Apparatus suitable for comminuting algae according to Claim 5, substantially as hereinbefore described 30 with reference to the accompanying drawing.